I treat it the same as when someone says, "I'll drink to your health". I say thank you, the more people on the case, the better. Seriously, why let it bother you? The underlying message is simply, "I care". Does it matter if they say it differently?.

I'm not easily offended to begin with. Even though, I know it doesn'y do anything, I usually ignore it. I think it's something theists like to say, but I believe very few actually do it. Either way it has no affect on me. Too many people these days are too easily offended. If it doesn't affect me, why should I let it bother me.